Closed-loop efficiency modulation for use in ac powered applications

Abstract

A system and method for closed-loop efficiency modulation for an AC / DC power system is provided. A boost-buck converter and a DC / DC converter connected in series receive a rectified DC feed signal from a AC input signal and deliver a modified DC output to an active load. A controller receives power data at various stages of the system and uses that data to modify a series of trim voltages provided to the feedback inputs of the respective converters to modify each converters output voltage. The controller modifies each converter's output voltage to maximize power efficiency while monitoring other data in the system to ensure the system is operating correctly and safely.

Description

BACKGROUND

[0001] 1. Technical Field

[0002] The embodiments relate generally to power efficiency in power supply systems.

[0003] 2. Description of Related Art

[0004] Engineers have historically used DC power supplies to act as a buffer between the equipment requiring electrical power and the primary electric power source. In the United States and many other nations, electric power is usually transmitted using AC power, which, in turn, requires some form of an AC / DC converter to convert the delivered AC power to a form that the equipment can properly use. Switching-mode DC power supplies convert AC voltage to DC voltage using components with low losses in power dissipation, such as capacitors, inductors, transformers, and switches (transistors, diodes etc).

[0005] The efficiency of a switching mode power supply (SMPS) varies depending on the load. For example, a SMPS operates at a much higher efficiency when fully loaded than at low loads. There are three main areas where one can increase effi...

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